: New invention 'harvests' electricity from background radiation and could be used to beam power to remote locations or recharge phones wirelessly

: Device captures microwaves and converts them into electricity

: Future versions could harvest satellite, sound or Wi-Fi signals

: Technology could be used to recharge phones without cables or beam electricity to mountaintops

: Engineers at Duke University have designed a breakthrough gadget that 'harvests' background microwave radiation and converts it into electricity, with the same efficiency as solar panels.

: The development, unveiled on Thursday, raises exciting possibilities such as recharging a phone wirelessly and providing power to remote locations that can't access conventional electricity.

: And the researchers say that their inexpensive invention is remarkably versatile. It could be used to capture 'lost' energy from a range of sources such as satellite transmissions, sound signals or Wi-Fi.

: The Duke engineers used metamaterials, which their press release describes as 'engineered structures that can capture various forms of wave energy and tune them for useful applications.'

: They say the device harvested microwaves with an efficiency of 36.8 percent, similar to modern solar cells that capture light energy.

: A report that will appear in the journal Applied Physics Letters in December states that this invention is capable of converting microwave signals to enough direct current voltage to recharge a cell phone battery.

: The gadget, created by undergraduate engineering student Allen Hawkes, graduate student Alexander Katko and lead investigator Steven Cummer, consists of five fiberglass and copper conductors wired together on a circuit board.

: It is capable of providing 7.3V of electricity. As the press release points out, current USB chargers provide around 5V.

: Hawkes said: 'We were aiming for the highest energy efficiency we could achieve. We had been getting energy efficiency around 6 to 10 percent, but with this design we were able to dramatically improve energy conversion to 37 percent, which is comparable to what is achieved in solar cells.'